Usage of asynchronous transfer mode ("ATM") networks for the transfer of multimedia information including video, voice and data has become increasingly popular due to the high data rate and flexibility of such networks. ATM networks use a packet switching technique standard specified by the CCITT, as described in M. dePrycker, Asynchronous Transfer Mode: Solutions from Broadband ISDN (Ellis Horwood, 1993). ATM networks have been embraced by the computer and telecommunication industries for networking existing and future multimedia applications, such as video conferencing, video-on-demand, and telephone applications. An ATM network is a connection-oriented network in which each transfer of data between network devices is preceded by a call to a network connection manager to establish a virtual circuit or connection between the devices. A virtual circuit corresponds to a particular routing path identified by the network connection manager for transmitting data between the devices. However, few commercially available computers are ATM compatible. Furthermore, presently available connections to the small number of existing ATM networks is limited due to the high cost of data routing switches currently used in the construction of ATM networks.
In contrast, computers or other processing systems which communicate with each other over a connectionless network, such as the Internet, are currently being used worldwide, and can be found in business offices, schools and in many homes. These networks are referred to as being connectionless because data is transferred over the network from a source device to a destination device without first establishing a "connection" or virtual circuit as is required in ATM networks.
Computers communicate over a connectionless network using any one of a number of protocols, such as the Internet Protocol ("IP"). Protocols provide for file transfer, remote log-in, electronic mail and other services, including distributed processing. The IP, among its other facilities, enables a data packet to traverse one or multiple networks from a source device to a final destination device. In a connectionless network, data is transmitted by a source device with an address of the destination device and the connectionless network will route that data by any number of network paths to the desired destination device.
The differences in these data transfer-techniques has been a major obstacle in linking the large numbers of computers and applications software available on connectionless networks, such as the Internet, with the devices and wide range of services expected to become available on ATM network. Differences in data packet formats used for transferring information on the respective networks has further hindered such linking of network systems.
Thus, a recognized need exists to establish communications and data transfer between connectionless and ATM networks.